In recent years, as weight reduction of vehicles is required, weight reduction of glass run channels is required. Thus, for example, a technique of forming a glass run channel from a foamable thermoplastic elastomer is known as disclosed in JP-A-2005-88718. In this technique, the glass run channel integrally includes a base portion (including a bottom wall portion, an interior lateral wall portion, an exterior lateral wall portion, an interior lateral wall connecting portion, and an exterior lateral wall connecting portion) and a lip portion, and the base portion is formed from the foamable thermoplastic elastomer.